Catheter incorporating a guidewire exit ramp

ABSTRACT

Guidewire exit ramp members that may be placed over a tubular member having a guidewire lumen, which longitudinally extending and laterally accessible, and methods of use. The guidewire exit ramp member can be placed to force a guidewire loaded through the lumen in a first direction to be forced out of the lumen via an opening, slit or channel. The guidewire exit ramp member, in an illustrative embodiment, takes the form of a relatively short member having a proximal portion and a distally extending flap. The flap may be designed to enter and remain in a longitudinally accessible guidewire lumen. Combinations of such ramp members and device shafts having longitudinally extending laterally accessible guidewire lumens are also disclosed, as are methods for securing such combinations together. A method of backloading a guidewire into a catheter while causing lateral exit of the guidewire at a desired location is also shown.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/917,974, filed Aug. 12, 2004, now abandoned the entire disclosure ofwhich is incorporated herein by reference.

FIELD

The present invention is related to the field of medical devices. Moreparticularly, the present invention is related to catheters and otherelongate medical devices incorporating guidewire lumens.

BACKGROUND

The use of catheters for minimally invasive medical procedures hasbecome widespread. In many such procedures, a guidewire is used to helpplace the distal end of a catheter at a desired location. In practice,the use of a guidewire and an elongate medical device such as a cathetercan create a number of difficulties.

If a guidewire or catheter proves unsuitable once inserted into apatient, it is removed and replaced. With early technologies, thecatheter typically tracked over the guidewire along its entire length.When a catheter was removed, these early technologies required allowingthe entire length of the catheter (typically 150 cm or longer) to passover the guidewire without releasing the proximal end of the guidewire.This required a guidewire having a length of at least 300 cm, or ashorter guidewire used in combination with a guidewire extension. Suchlong guidewires required extra hands in the operating arena, increasingcosts and creating a greater risk of loss of sterility, as well asmaking procedures last longer.

Rapid exchange catheters and single operator exchange catheters havebeen developed to make it easier and quicker to substitute one catheteror guidewire for another. An example single operator exchange catheteris the Autotome™ RX sphincterotome, marketed by Boston ScientificCorporation, Natick, Mass., which makes use of an elongated guidewirelumen in the form of a C-shaped channel.

The C-shaped channel allows lateral movement of a guidewire out of theguidewire lumen through the opening in the C-shaped channel over thelongitudinal length of the channel. Such an opening, as well as openingsor accesses created by the use of C-shaped, U-shaped, perforated or slitguidewire lumens, makes the longitudinally extending guidewire lumen alaterally accessible guidewire lumen. Lumens having a weakened, thin, orthinned wall through which a guidewire may tear for removal may also beconsidered as including a laterally accessible guidewire lumen.

SUMMARY

The present invention, in an illustrative embodiment, includes aguidewire exit ramp member that may be placed over a tubular memberhaving a longitudinally extending guidewire lumen that is laterallyaccessible generally continuously over at least a portion of the lengthof the tubular member. The guidewire exit ramp member can be placed toforce a guidewire passing into the guidewire lumen in a first directionto be forced out of the lumen via an opening, slit or channel. Theguidewire exit ramp member, in an illustrative embodiment, takes theform of a ramp member having a proximal portion and a distally extendingflap. The flap may be designed to enter and remain in a longitudinallyextending laterally accessible guidewire lumen.

Another illustrative embodiment includes a method of providing aguidewire exit location for an elongate medical device. A guidewire exitramp member is placed on an elongate member having a longitudinallyextending guidewire lumen with a slit or opening therein over a certainlength. The elongate member may include a skive or other opening intothe guidewire lumen. The guidewire exit ramp member is placed near theskived portion or opening and slid in a direction such that a flap ofthe guidewire exit ramp member goes through the skive into the guidewirelumen. In some embodiments, the guidewire exit ramp member may besecured in place by heat bonding, adhesive, or the other attachmentmethods. When the method is complete, a guidewire passed through theguidewire lumen in a first direction is forced out of the guidewirelumen by the flap of the guidewire exit ramp member. In a furtherembodiment, the flap is flexible enough such that, when a guidewire ispassed through the guidewire lumen in a second direction, the guidewirereadily passes by the flap with little or no added resistance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a partial elevational view of a medical device shaft having alongitudinally extending laterally accessible guidewire lumen;

FIG. 1B is a cross-sectional view along line 1B-1B of FIG. 1A;

FIG. 2 is a plan view of a cannula including a longitudinally extendinglaterally accessible guidewire lumen;

FIG. 3 is a perspective view of a guidewire exit ramp member for use inconjunction with a medical device shaft having a longitudinallyextending laterally accessible guidewire lumen;

FIG. 4 is an elevation view of the illustrative guidewire exit rampmember of FIG. 3 showing the flap;

FIG. 5 is a side view of the illustrative guidewire exit ramp member ofFIG. 3;

FIG. 6 is an end view from a distal location of the illustrativeguidewire exit ramp member of FIG. 3;

FIG. 7 is an elevation view of an alternative example guidewire exitramp with a curved flap;

FIG. 8A is an elevation view of an illustrative guidewire exit rampcoupled with a medical device shaft having a longitudinally extendinglaterally accessible guidewire lumen;

FIG. 8B is a section view along line 8B-8B of FIG. 8A;

FIGS. 9A-9C are section views along lines 9A-9A, 9B-9B, and 9C-9C ofFIG. 8A;

FIGS. 10A-10C, 11A-11C, and 12A-12C illustrate placement of a guidewireexit ramp on another medical device shaft having a closed longitudinallyextending laterally accessible guidewire lumen;

FIGS. 13A-13C illustrate in elevation and section views an alternativeembodiment using a relatively stiff plastic guidewire exit ramp member;and

FIGS. 14A-14C illustrate placement of the embodiment of FIGS. 13A-13B onan elongate medical device shaft.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

FIG. 1A is a partial elevational view of a medical device shaft having alongitudinally extending laterally accessible guidewire lumen. The shaft10 includes a channel 12 for laterally accessing a guidewire lumenpassing therethrough. FIG. 1B is a cross-sectional view along line 1B-1Bof FIG. 1A. As illustrated by FIG. 1B, the guidewire lumen 14 includesthe channel 12. Two auxiliary lumens 16, 18 are also illustrated. Whilea triple lumen shaft 10 is illustrated, any number of lumens, from asingle lumen up to 3, 4, or more lumens, may be provided in a shaft foruse with the present invention.

The channel 12 is illustrated for providing access to a generallyU-shaped guidewire lumen. Instead of a U-shape, a C-shape opening may beprovided, the C-shape helping to retain a guidewire in the lumen 14.Additionally, a slit may be used. Alternatively, instead of a channel 12creating an opening, a wall for the lumen 14 where the channel is shownmay be thin or intentionally thinned to enable a guidewire to be torntherethrough. Perforations may also be provided to make thelongitudinally extending guidewire lumen 14 laterally accessible.Laterally accessible, as used herein, refers to a guidewire lumen thatcan be accessed along a length thereof, where access can be had eitherthrough an existing opening or by tearing a guidewire disposed in theguidewire lumen laterally through a slit, thin, thinned, perforated, orotherwise relatively weak lumen wall section.

FIG. 2 is a plan view of a cannula including a longitudinally extendinglaterally accessible guidewire lumen. The cannula 20 may incorporate ashaft 10 as illustrated in FIGS. 1A and 1B having a distal end 22 and aproximal end 24. A slit 26 extends along a length of the shaft towardthe distal end 22; while not shown, the slit 26 may extend proximally toa guidewire entry adaptor 28. The example also illustrates marker bandsnear the distal end. Proximal of the adaptor 28 is a manifold 30including two fluid infusion ports. The cannula in FIG. 2 may have asimilar cross section to that shown in FIG. 1B, except to the extentthat a slit 26 is used instead of a an opening. The fluid infusion portson the manifold 30 may be coupled to the auxiliary lumens of the cannulashaft for infusing fluids to a location at or near the distal end 22.

The adaptor 28 shown functions by having a side-directed ramp/lumen withan opening allowing for lateral removal of a guidewire therefrom. Theproximal end of the guidewire is controlled proximal of the adaptor 28such that there is no need to force a backloaded guidewire from theguidewire lumen. The guidewire can be removed through the slit 26 oncethe exchange procedure starts. However, the exact location where theguidewire exits the slit 26 is not controlled. In particular, if aguidewire is backloaded into such a rapid exchange catheter, the adaptor28 does not force the guidewire out of the catheter.

An example and description of such an adaptor 28 is given by Windheuseret al., in U.S. Pat. No. 6,606,515, the disclosure of which isincorporated herein by reference. The adaptor 28 has a relatively largeprofile in order to achieve ease of guidewire entry through afunnel-shaped portion, as further discussed by Windheuser et al., and isdesigned to prevent passage of the entire adaptor through a side port inan endoscope. Such sizing would also typically prevent passage through aguide catheter used in a vascular procedure.

During a catheter exchange procedure, with the guidewire already inplace at a desired location in the patient (i.e., a vascular location, alocation in the biliary tract, or any other cannulated location), theguidewire will extend through the guidewire lumen from the adaptor 28 tothe distal end 22. To exchange the cannula 20, the guidewire is movedlaterally out of the adaptor 28 and held in place as the cannula 20 iswithdrawn. As the cannula 20 is withdrawn, the guidewire passes throughthe slit 26, remaining in its internal location in the patient withoutrequiring a guidewire extension. The slit 26 may extend to the distalend 22, or may stop proximal of the distal end.

FIG. 3 is a perspective view of a guidewire exit ramp member for use inconjunction with a medical device shaft having a longitudinallyextending laterally accessible guidewire lumen. The illustrative exampleguidewire exit ramp member includes a proximal portion 50, a proximalend 53, a flap 52, a distal portion 54, and a distal end 55. The distalportion 54 of the guidewire exit ramp may further include a slot 51defined therein. The proximal portion 50 surrounds and/or tracks over anelongate medical device on which the guidewire exit ramp member is used.The shape is shown as cylindrical but may instead be oval, polygonal, orother shapes including polygons with one or more curved sides.

In other illustrative examples, the proximal portion 50 may only partlysurround an elongate medical device, and may instead take the form of apartial cylinder, or may have one or more gaps. In several embodiments,the form illustrated in FIG. 3 is used for its low profile, allowing theguidewire exit ramp member to be readily placed and used even insituations where low profile is a concern.

FIG. 4 is an elevation view of the illustrative guidewire exit rampmember of FIG. 3 showing the flap 52 more clearly. The flap 52 may havea proximal end 57 connected to the proximal portion 50 of the guidewireramp member and extending distally therefrom to a distal end 59. In someinstances, the distal end 59 of the flap may be flat. As can be seen,the example flap 52 has rather angular distal ends, extending distallyrelative to, but shorter than, the distal portion 54. In otherembodiments the flap 52 may be longer than the distal portion 54, and,in one embodiment, the distal portion 54 may be entirely omitted. Forsome embodiments, the flap 52 will be inserted through a transverselycut opening in an elongate medical device, as further explained below.For such embodiments, the inclusion of the distal portion 54 may helpmaintain the shape, pushability, and/or anti-kinking characteristics ofthe elongate medical device across the transverse cut since thetransverse cut may weaken the elongate medical device.

FIG. 5 is a side view of the illustrative guidewire exit ramp member ofFIG. 3. The distal portion 54 has a reduced profile due to the flap 52.FIG. 6 is an end view of the illustrative guidewire exit ramp member ofFIG. 3. The flap 52 is shown extending down into the lumen defined bythe distal portion 54, which is in line with the lumen formed in theproximal portion 50. In an illustrative embodiment, the flap 52 isbiased to bend down as illustrated by FIGS. 3 and 5-6.

In one embodiment, the guidewire exit ramp member shown in FIGS. 3-6 isformed by a molding process. In other embodiments, the guidewire exitramp member may be formed by cutting a tubular member. The ramp membermay be sized to correspond to a given size of elongate medical deviceshaft. For example, given a 6-French elongate medical device shaft, theinner diameter defined by the proximal portion of the ramp member may bejust large enough to slide over such a device shaft. The inner surfaceof the ramp member may include a lubricious coating to allow easymovement and placement over the device shaft. Alternatively, thematerial chosen for making the ramp member may be chosen for itslubricious properties.

The ramp member may be formed of a wide variety of materials. In someembodiments the ramp member is formed of a nylon material, which isinexpensive and easy to mold, as well as being a popular material formedical applications. Polycarbonate may also be used, as well as any ofa wide variety of polymers, copolymers and metals or alloys known foruse in medical devices, catheters, cannulas, endoscopes, and the like.Any other suitable biocompatible material may also be used and/orincorporated.

FIG. 7 is an elevation view of an alternative example guidewire exitramp member with a curved flap. As illustrated, the guidewire exit rampmember includes a proximal portion 60, a proximal end 63, a flap 62, a(optional) distal portion 64, and a distal end 65. The distal portion 64of the guidewire exit ramp may further include a slot 61 definedtherein. As shown at 66, the flap 62 has curved ends, which may allowthe flap 62 to extend into and generally match the contours of aguidewire lumen having curved interior contours. Rather than a simplecurve as shown, the flap 62 may be designed to match a particularguidewire lumen shape/cross section.

FIG. 8A is an elevation view of an illustrative guidewire exit rampcoupled with a medical device shaft having a longitudinally extendinglaterally accessible guidewire lumen. A device shaft 100 is shown with aguidewire exit ramp member 102 placed thereover. The ramp member 102 mayinclude a proximal end 103 and a distal end 105. The ramp member 102 mayfurther include a slot 101 extending proximally from the distal end 105.The ramp member 102 includes a flap 104 having a proximal end 107 and adistal end 109. The flap 104 is aligned with and enters a channel 106(shown as a U-shaped channel for the purposes of illustration). Thelongitudinal cross section of FIG. 8B illustrates that the ramp member102 has a proximal portion that surrounds the device shaft 100, with theflap 104 extending down into the channel 106.

The transverse section views of FIGS. 9A-9C illustrate that the deviceshaft 100 is shown having the channel 106 as well as auxiliary lumens108 and 110. As shown in FIG. 9B, along line 9B-9B in FIG. 8A, the flap104 extends partly into the channel 106, with the optional distalportion of the ramp member 102 extending around the device shaft 100 atthat location. FIG. 9C is taken at a more distal location along thedevice shaft 100 and ramp member 102, as shown by line 9C-9C of FIG. 8A.By this point, the flap 104 extends down to the base of the channel 106.If a guidewire is backloaded into the channel 106, the flap 104 willforce the guidewire out of the channel 106. However, if a guidewire ispassed distally from a more proximal location, as can be seen in FIG.8B, the slant of the flap 104 will allow the flap 104 to deflect so thatthe guidewire may pass with little resistance generated by the flap 104.

FIGS. 10A-10C, 11A-11C, and 12A-12C illustrate placement of a guidewireexit ramp on another medical device shaft having a closed longitudinallyextending laterally accessible guidewire lumen. Referring to FIGS.10A-10C, a guidewire exit ramp member 200 having a flap 202 is shownplaced on a device shaft 204, the device shaft 204 having an openingshown as skive 206. The ramp member 200 may include a proximal end 203and a distal end 205. The ramp member 200 may further include a slot 201extending proximally from the distal end 205. The flap 204 may have aproximal end 207 and a distal end 209. The ramp member 200 is shown somedistance proximal of the skive 206 on the device shaft 204.

As highlighted in FIG. 10B, (a section view along line 10B-10B of FIG.10A) the device shaft 204 includes a guidewire lumen 208 having athinned wall 210, as well as an additional auxiliary lumen 212. Thethinned wall 210 enables a guidewire to laterally exit the guidewirelumen 208 by tearing through the thinned wall 210. To further weaken thewall, perforations may be provided. The thinned wall 210 may be providedduring extrusion or by post-extrusion machining. The longitudinal crosssection of FIG. 10C illustrates the skive opening into the guidewirelumen 208.

Turning to FIGS. 11A-11C, FIG. 11A shows that the ramp member 200 hasbeen advanced such that the flap 202 partly enters the skive 206 in thedevice shaft 204 such that the distal end 209 is disposed within theguidewire lumen 208. FIG. 11B shows in transverse cross section that theflap 202 reaches partly down into the guidewire lumen 208 through theskive 206. As shown by FIG. 11C, the skive 206 enables easy entry of theflap 202 down into the guidewire lumen 208 through the thin wall 210. Insome embodiments, the flap 202 may be biased downward such that itreadily extends through the skive 206. It should be noted that thethinned wall 210 would not be necessary to use the guidewire ramp member200 in the fashion shown, since the flap 202 simply enters through anopening into the guidewire lumen 208.

Referring now to FIGS. 12A-12C, the ramp member 200 is moved distallyalong the device shaft 204 until the flap 202 completely enters theguidewire lumen 208 through the skive 206. Once this location isreached, the flap 202 may rest against an interior wall of the guidewirelumen 208. When so located, a guidewire proximal end passing in aproximal direction through the guidewire lumen 208 may be forcedlaterally out of the device shaft 204 by the flap 202. Thus backloadingof a guidewire into the device shaft 204 can be performed easily with anassurance that a guidewire will exit the device shaft 204 at a desiredlocation defined by the skive 206 and the ramp member 200. In variousillustrative embodiments, the ramp member 200 may be moveable withrespect to the shaft or secured (by adhesive or welding, for example) tothe device shaft 204 once placed as shown in FIG. 12A.

FIGS. 13A-13C illustrate in elevation and section views of analternative embodiment making use of a pinch or squeeze type of ramp. Ascan be seen, the ramp member 300 includes a proximal portion 302 and apinching portion 304. The pinching portion 304 may be sized to reducethe internal diameter or cross-sectional area of the ramp membersufficient to collapse a portion of a guidewire lumen. In oneembodiment, the reduced diameter/area is sized to prevent pinching ofany auxiliary lumens of an associated medical device, though somecompression may be acceptable. It should be noted that the pinchingportion need not be cylindrical and may take on a variety of shapesadapted for use with various catheter shafts. As shown in FIG. 13C, thetransverse section of the pinching portion 304 is shaped to receive acatheter shaft without pinching any auxiliary lumens, instead beingshaped to compress only the guidewire lumen. The dashed lines of FIG.13C represent, in phantom, the locations of a guidewire lumen and twoauxiliary lumens for a catheter shaft received and pinched by the rampmember 300. It can be seen that two of the lumens (the auxiliary lumens)would not be significantly blocked.

FIGS. 14A-14C illustrate placement of the embodiment of FIGS. 13A-13B onan elongate medical device shaft. As shown in FIG. 14A, the elongatemedical device shaft 310 is provided with a transverse cut 312 that maytake the form of a skive or slit. If desired, the shaft 310 may includea guidewire lumen having a thinned or weakened wall. As shown in FIG.14B, the ramp member 300 is slid onto the shaft 310 until the rampmember 300 engages the transverse cut 312. At the location of thetransverse cut 312, the shaft 310 will be inherently weaker due to thetransverse cut 312 across a portion of the wall of the guidewire lumen.Turning to FIG. 14C, it can be seen that the ramp 304 of the ramp member300 collapses a portion of the wall of the guidewire lumen 314, but theauxiliary lumen 316 is not significantly affected. The proximal portion302 aids in letting the ramp 306 collapse the wall of the guidewirelumen 314. A guidewire backloaded into the shaft 310 will now be forcedout of the guidewire lumen 314 at the ramp 304. Any suitable plasticsmay be used for the shaft 310 and the ramp member 300. For thealternative embodiments of FIGS. 13A-13B and 14A-14C, the ramp member300 may be formed of a stiffer material than the material used to definethe guidewire lumen 314. To preserve the patency of the auxiliary lumen316, some embodiments may make use of a reinforcing member to supportthe auxiliary lumen 316.

Those skilled in the art will recognize that the present invention maybe manifested in a variety of forms other than the specific embodimentsdescribed and contemplated herein. Accordingly, departures in form anddetail may be made without departing from the scope and spirit of thepresent invention as described in the appended claims.

1. A combination comprising: an elongate medical device comprising anelongate shaft portion having a longitudinally extending laterallyaccessible guidewire lumen, the guidewire lumen accessible through anopening in the elongate shaft portion; and a generally tubular guidewireexit ramp member having a proximal portion, a distal portion, and a flapmember, the proximal portion having a lumen, the distal portion having alumen and a slot extending proximally from a distal end of the distalportion to a proximal end of the flap member, the flap member extendingdistally from the proximal portion and further being biased to extendinto the lumen defined by the distal portion; and wherein the rampmember is positioned on the elongate shaft portion such that theproximal portion and distal portion surround the elongate shaft portionand the flap member extends into the guidewire lumen such that aguidewire backloaded into the guidewire lumen will be forced out of theguidewire lumen through the opening by the flap member.
 2. Thecombination of claim 1, wherein the guidewire lumen is defined by aC-shaped channel.
 3. The combination of claim 1, wherein the guidewirelumen is defined by a U-shaped channel.
 4. The combination of claim 1,wherein the flap member comprises a flat end.
 5. The combination ofclaim 1, wherein the flap member comprises a curved end.
 6. Thecombination of claim 1, wherein the flap member comprises a distal endshaped to correspond to a portion of the guidewire lumen.
 7. Thecombination of claim 1, wherein the flap member is flexible such that aguidewire passing from a location proximal of the ramp member within theguidewire lumen is readily allowed past the flap member in the guidewirelumen.
 8. The combination of claim 1, wherein the ramp member is securedto the elongate shaft portion.
 9. The combination of claim 1, whereinthe elongate medical device further includes an auxiliary lumen inaddition to the guidewire lumen.